Collapsible feed mechanism

ABSTRACT

This disclosure is directed to a collapsible feed mechanism for advancing and retracting a rod or rod-like member, and in particular a &#39;&#39;&#39;&#39;slender column,&#39;&#39;&#39;&#39; which may be subjected to large compressive axial loads. The collapsible feed mechanism disclosed herein comprises a plurality of aligning plates and a drive plate all slidably mounted within a support cage. Power cylinders, connected to the drive plate by piston rods, advance and retract the rod, or slender column, which is also connected to the drive plate. The aligning plates and drive plate cooperate to centrally position, advance and retract the rod or slender column, e.g., an extrusion die ram, without bending or buckling the column, even when subjected to large compressive axial loads, e.g., the force of extrusion necessary to advance the die ram upwardly of a billet confined in a high pressure vessel, to extrude the billet into wire.

United States Patent Fuchs, Jr. [451 Apr. 3, 1973 COLLAPSIBLE FEED MECHANISM Primary Examiner-Milton Kaufman 75 Inventor: Francis ose hFuchs r. Princeton AssistamExammerRonald l 1 Junctio: 3 J Attorney-H. J. Winegar, R. P. Miller and W. M. Kain [73] Assignee: Western Electric kCompany, Incor- [57] ABSTRACT t d N Y N.Y. pom e ew or ThlS d1sclosure 1s dlrected to a collapsible feed [22] Flledi Ju y 28, 1970 mechanism for advancing and retracting a rod or rodlike member and in articular a slender column 21 A LN .z64892 P 1 1 PP 0 i which may be subjected to large compressive axial Related US. Application D t loads. The collapsible feed mechanism disclosed Divisi n fs N 651292 Jul 5 1967 P t N herein comprises a plurality of aligning plates and a 3 y a drive plate all slidably mounted within a support cage. Power cylinders, connected to the drive plate by piston rods, advance and retract the rod, or slender CCll column which is also connected to the drive plam [58] Fie'ld 66 62 The aligning plates and drive plate cooperate to cen- 253 trally position, advance and retract the rod or slender column, e.g., an extrusion die ram, without bending or buckling the column, even when subjected to large [56] References cued compressive axial loads, e.g., the force of extrusion UNITED STATES PATENTS necessary to advance the die ram upwardly of a billet con me in a 1 ressure vesse to extru e t e 1 et 451846 /89 B h f d hghp l d h bu 51 1 ac man ..92/62 t 3,107,933 l0/l963 Royster ..92/25 m o wlre 25 Claims, 6 Drawing Figures COLLAPSIBLE FEED MECHANISM CROSS REFERENCE TO RELATED APPLICATION This application is a division of application Ser. No. 651,292, filed July 5,1967, now US. Pat. No. 3,548,625.

BACKGROUND OF THE INVENTION A problem which has faced those concerned with the extrusion art, as well as other arts wherein it is required to advance a rod, or rod-like member, and in particular a slender column, subjected to a relatively high compressive axial load, has been the bending or buckling of the member. A further problem has been that of maintaining such a member in co-axial alignment with other structure during such advancement.

It is known to those skilled in the art, that long, slender rods having a length to least radius of gyration ratio in excess of 80 to l, are particularly susceptible to bending and buckling when subjected to large axially directed, compressive loads. These rods are known as long and slender columns. The concept oflong and slender columns is treated in Engineering Design," Joseph H. Faupel, published by John Wiley & Sons Inc. in 1964. Accordingly, it will be understood that the shortened expression slender column, as will be used in this specification and the appended claims, is used in this context.

The susceptibility of rods in general, and slender columns in particular, to bending and buckling not only limits the capability of the rod or column to support axially directed compressive loads, but also causes misalignment and bending difficulties when it is necessary to pass a rod or slender column axially through one or more aligned orifices. For example, the extrusion of wire from a billet being subjected to high hydrostatic pressure in a fluid tight pressure vessel, wherein the extrusion is accomplished by advancing a ram-mounted die upwardly of the billet into a bore in the vessel, ordinarily requires the use of 'a hollow die ram which is a rod, or rod-like member, categorizable as a slender column. The forces of extrusion are relatively high, thus increasing the likelihood of bending or buckling. Further, the alignment of the die ram with the pressure vessel bore is very important in order to preclude binding which might interfere with advancement of the die at a constant or controlled rate. In this exemplary situation, therefore, great care must be taken to impart the force for advancing the die ram in a solely axial direction, to support the die ram against any unacceptable bending or buckling, and to maintain the die ram in co-axial alignment with the pressure vessel.

SUMMARY OF THE INVENTION This object, and others which will be recognized readily by those having skill in this art, is achieved by the present invention wherein there is provided apparatus for advancing a rod-like member, which apparatus includes driving means for transmitting advancement forces to the ro'd-like member to advance the member, support means for supporting and positioning the driving means co-axially with respect to the rod-like member during the advancement thereof, alignment means supported and positioned co-axially of the rod-like member by the support means and for radially supporting the rod-like member during the advancement thereof, and the alignment means comprising at least one plate member axially displaceable in response to the advancement of the driving means.

It is'the object of the present invention, therefore, to provide an apparatus for advancing rods in general, and slender columns in particular, which are subjected to relatively high compressive axial loads, which apparatus is capable of transmitting the force necessary for advancement, and capable of providing adequate radial support to the rod or column to preclude buckling or bending thereof and maintain desired relative co-axial alignment.

BRIEF DESCRIPTION OF THE DRAWINGS The exact nature, as well as the many attendant advantages of the present invention will become more readily understood by a consideration of the following detailed description thereof when read in the light of the annexed drawings wherein:

FIG. 1 is a longitudinal view, partly in cross-section, of a collapsible feed mechanism according to the present invention;

FIG. 2 is a longitudinal view of the collapsible feed mechanism similar to that of FIG. 1, but showing the mechanism partially advanced;

FIG. 3 is a fragmentary view of the collapsible feed mechanism, similar to those of FIGS. 1 and 2, and showing the rod or slender column in the fully advanced position;

FIG. 4 is a cross-sectional view through the plane 4- 4 of FIG. 1;

FIG. 5 is a cross-sectional view through the plane 5 5 SofFIG. l;and

FIG. 6 is a cross-sectional view through the plane 6 6 of FIG. 5, showing a locking mechanism suitable for use with the collapsible feed mechanism of the present invention.

DETAILED DESCRIPTION Referring now to FIGS. l-3, and FIG. 1 in particular, a collapsible feed mechanism according to the present invention is designated generally by the reference numeral 10. The collapsible feed mechanism 10 is shown being utilized with an extrusion apparatus to advance a die ram 12 to extrude a billet 14 into wire; the die ram being definable as a slender column since its ratio of length to least radius of gyration is well in excess of of l. The billet 14 is contained in a high pressure vessel 16 and may be subjected therein to a high hydrostatic pressure sufficiently great to cause the billet to increase in ductility so as to be deformable without fracture. An extrusion die 18 formed integrally with, or mounted on the front end of the die ram 12, is slidably and reciprocably received within the pressure vessel 16, and together, die ram 12 and die 18 are driven through the feed mechanism 10 by an array of double acting,

0 power cylinders 22 mounted concentrically around the high pressure vessel 16.

Structurally, collapsible feed mechanism 10 comprises a stationary cage 11 having a series of reciprocably movable elements mounted therein. As will be recognized by those skilled in the art, the feed mechanism may be supported in any suitable manner, such as by mounting on a base or by insertion in a cylindrical support. In that the mode of support of the feed mechanism 10 is not critical to a complete understanding of the present invention, and in the interest of drawing clarity, no support structure has been shown. It is to be understood, however, that in typical use, the feed mechanism 10 is suitably supported.

As can be best seen in FIGS. 1 and 4, the collapsible feed mechanism 10 includes a plurality of spaced coaxial rings 26 mounted in slots 27 formed in longitudinally extending rails 28. Rails 28, which are generally rectangular in cross section, extend longitudinally parallel to the longitudinal center line of die ram 12 and are symmetrically disposed along radii emanating therefrom.

The inner portions 29 of the rails cooperate to define tracks along which a plurality of aligning plates 30, 31 and 32, and a drive plate 33, slidably reciprocate. The tracks defined by rails 28 position the plates 30 through 33 along a common central axis, which axis corresponds to the longitudinal axis of the die ram 12. As may be best seen in FIGS. 4 and 5, the aligning plates 30, 31 and 32, and drive plate 33, are each a circular plate having a plurality of symmetrically disposed, radially extending, generally rectangular notches 35 formed around the periphery thereof for slidably receiving the inner portions 29 of rails 28. Each aligning plate 30, 31, 32 (as shown in FIG. with regard to aligning plate 31) is provided with a centrally formed aperture 34 for slidably receiving the die ram 12 therethrough. Drive plate 33, best seen in FIG. 1, is also provided with a centrally formed aperture 38, however aperture 38 is smaller in diameter than apertures 34, being only large enough to allow the free passage of the extruded product 20 therethrough. The drive plate 33, as well as aligning plates 30, 31, 32, are all provided with a plurality of radially disposed axially extending holes, the purpose of which will be set forth fully hereinafter. 7

Referring back to FIGS. 1-3, driving rods 40, one from each power cylinder 22, extend slidably through apertures 41 provided in aligning plates 30, 31, 32. The free ends of rods 40 are threadedly secured to the drive plate 33 for positioning plate 33 generally perpendicularly to the longitudinal axis of die ram 12 and for transmitting driving motion directly, and solely, to the drive plate 33 for both the advancement and retraction thereof; the rods 40 transmitting no motion directly to the aligning plates. r

The drive plate 33 is secured, such as by bolts, 37, to a shoulder 39 formed on the butt end of die ram 12 and the drive plate transmits advancement and retraction motion directly to the die ram 12. The aforementioned centrally disposed aperture 38 formed in drive plate 33 is in axial alignment with a central passageway 42 (FIG. 1) provided longitudinally through die ram 12 to accommodate the discharge of extrusion product 20.

Three longitudinally disposed headed bolts 51, (only two shown in FIGS. 1 and 2 for clarity) are slidably received within apertures 61 (FIG. 4) provided in the drive plate 33, and are threadedly secured to the aligning plate 32. The heads 71 of the bolts 51 are larger than the apertures 61, and accordingly, when the feed mechanism is in its fully extended position as shown in FIG. 1, the bolt heads 71 are in engagement with the outer surface of the drive plate 33 in the manner shown in FIG. 1.

Similarly, three longitudinally disposed headed bolts 52 are slidably received within apertures 62 (FIG. 1 provided in the aligning plate 32, and are threadedly secured to the aligning plate 31. The heads 72 of the bolts 52 are larger than the apertures 62, and engage the outer surface of the aligning plate 32 when the collapsible feed mechanism 24 is extended to at least the position shown in FIG. 2. Further, it will be understood, that three longitudinally disposed headed bolts 53 having heads 73 (shown in broken line in FIG. 1) structurallyinterrelate aligning plates 30 and 31 in the same manner as described above with respect to bolts 51, 52, and plates 33, 32 and 31, respectively.

Drive plate 33, as shown in FIG. 4, is provided with a plurality of radially disposed apertures 55 of a diameter sufficiently large to accommodate the unobstructed passage therethrough of bolt heads 72 and 73 when the drive plate has been advanced to the position shown in FIG. 3. Similarly, aligning plate 32 is provided with oversized apertures (not shown) for accommodating the passage therethrough of bolt heads 73 as the feed mechanism 24 is collapsed.

In order to insure complete collapse of feed mechanism 10 and full advancement of die ram 22, a counterbore 36 is provided in aligning plate 32 for receiving die ram shoulder 39 therein when the mechanism is collapsed as shown-in FIG. 3.

The function of aligning plates 30, 31 and 32 is twofold, to maintain the die ram 12 in close centerline alignment with the central bore of high pressure vessel 16, and to provide radial support to the die ram 12 during extrusion when it is subjected to particularly heavy compressive axial loads, so as to preclude bending or buckling which would render the mechanism effectively inoperable. To these ends, aligning plates 30, 31 and 32 are uniformly spaced longitudinally of the die ram 12 in the initial positions as shown in FIG. 1, and are maintained in this uniform spacing during advancement of the die ram 12 until they are successively positively displaced by the forward movement of the ad- .vancing drive plate 33. Accordingly, each aligning plate 30, 31, 32 is provided with a cam latch assembly designated generally by the reference numeral 80, and shown in FIGS. 5 and 6, particularly FIG. 6. The cam latch assemblies are mounted peripherally of the aligning plates 30, 31, 32, each latch being angularly displaced with respect to the others, around the longitudinal center line of die ram 12. Each cam latch assembly cooperates individually with a single notch 84 formed in the surface 29 of a separate rail 28, no one rail being provided with more than one notch.

Referring specifically to FIG. 6, a representative cam latch assembly is mounted in a suitable recess 81 formed in one of the respective aligning plates. A plunger 82 is biased upwardly by a coil spring 90, and extends upwardly through an aperture 83 beyond the periphery of the aligning plate so as to be engageable with a notch 84-formed in the surface 29 of a rail 28. Plunger 82 is provided with beveled surfaces 85 which define cam surfaces for cooperative engagement with the complementarily shaped cam surfaces 86 of the notch 84. A generally V-shaped rocker arm 87, pivotally mounted on a pin 93 within the recess 81, is biased for clockwise rotation around pin 93 by bias spring 91. When the rocker arm 87 is pivoted into the solid line position shown in FIG. 6, a plunger engaging portion 89 maintains plunger 82 in its upwardly extended, notch engaging position. Further, when the plunger engaging portion 89 is so positioned, plate engaging portion 88 extends outwardly past the surface plane of the associated alignment plate, so that when the drive mechanism is being collapsed by the advancement of drive plate 33, the plate engaging portion 88 will be engaged by the next preceding aligning or drive plate, as appropriate, and such engagement will cause the rocker arm to pivot counterclockwise, as shown in FIG. 6, and into the position shown by the broken lines. Plunger engaging portion 89, therefore, will be pivoted out of engagement with plunger 82 thus allowing the plunger to be cammed inwardly, out of engagement with notch 84.

Operation The operation of the collapsible feed mechanism of the present invention will now be set forth. For purposes of description, it will be assumed that at the commencement of extrusion, the elements comprising the collapsible feed mechanism occupy the positions shown in FIG. 1, and that the billet 14 is contained within the high pressure vessel 16 under high hydrostatic pressure, as discussed above.

Appropriately pressurized fluid from a suitable supply (not shown) is admitted into the power cylin ders 22 so as to force the driving rods 40, and therewith the drive plate 33, to the left as viewed in FIGS. 1-3; the drive plate sliding along the track defined by rails 28. The drive plate 33, being secured to the die ram shoulder 39, in turn, displaces the die ram 12 to the left, as viewed in FIG. 1, into the billet containing vessel 16, and upwardly of the billet 14 thereby extruding the billet through die 18 to form wire 20. As the drive plate 33 and the die ram 12 move to the left, from the position shown in FIG. 1 toward the position shown in FIG. 2, aligning plates 30, 31 and 32 remain stationary, locked by cam latch assemblies 80 in the positions shown, while the die ram 12 slides relative thereto through apertures 34, the aligning plates thus providing radial support to the advancing die ram. I

As the drive plate 33, and therewith the die ram 12, are displaced continuously to the left by the action of power cylinders 22 acting through rods 40, the drive plate engages the plate engaging portion 88 (FIG. 6) of rocker arm 87 of the cam latch assembly 80 mounted in aligning plate 32. Continued advancement of drive plate 33 pivots the rocker arm 87 in a counterclockwise direction against the bias of spring 91, thereby disengaging the plunger engaging portion 89 of the rocker arm from the underside of plunger 82. Still further advancement of drive plate 33 results in engagement thereof with aligning plate 32, as shown in FIG. 2, and thereafter the now unlatched aligning plate 32 will move to the left with drive plate 33. As the aligning plate is moved, the rail cam surface 86, as best seen in FIG. 6, and the plunger cam surface 85, will, cooperatively, cam the plunger 82 downwardly against the action of the compression spring 90, thus allowing unobstructed axial displacement of aligning plate 32 with drive plate 33.

As aligning plate 32 is advanced continuously to the left with drive plate 33 and the die ram 12, it engages the rocker arm 87 of the cam latch assembly 80 mounted in aligning plate 31, and unlocks aligning plate 31 in the same manner as discussed above with respect to aligning plate 32. Thereafter, aligning plate 31 advances to the left with drive plate 33, aligning plate 32 and die ram 12, and in the same manner as described before with respect to the other plates, unlatches and engages aligning plate 30 for advancement toward billet containing vessel 16. Upon completion of the full advance of the die ram 12, the feed mechanism is fully collapsed, and the aligning plates, drive plate, and die ram occupy the positions shown in FIG. 3.

It will be readily recognized by those skilled in this art, after considering the above described advancement operation, that the drive plate 33 transmits solely axially directed force to the die ram 12, of sufficient magnitude to advance the die 18 upwardly of the billet 14 to cause extrusion and production of wire 20. Further, it can be seen that spaced lateral or radial support for the die ram 12 is provided at all times by the aligning plates 30, 31 and 32. It will also be understood that the die ram is maintained in close center line alignment with the bore of pressure vessel 16 and billet 14, so as to preclude the ram from ram bending or buckling.

Upon completion of the advancement of die ram 12, pressurized fluid is suitably admitted to power cylinders 12 to force rods 40, and therewith drive plate 33, to the right as viewed in FIGS. l-3, thus retracting the feed mechanism for a subsequent extrusion cycle. Retraction of drive plate 33 causes the retraction and positioning of alignment plates 30, 31 and 32 by lost motion linkage comprised of the headed bolts 51-53 and apertures 55, in a manner presented in detail hereinafter.

Referring again, therefore, to FIGS. 1 and 2; and in particular to bolts 51, it can be seen that, during the advancement of die ram 12, as the drive plate 33 moves from the position shown in FIG. 1 to the position shown in FIG. 2, it moves longitudinally of the bolts 51 and relative to the bolt heads 71, which bolts are fixedly secured to the aligning plate 32; such movement being permitted by the apertures 62 (FIG. 4) formed in drive plate 33, which apertures are larger in diameter than the diameter of bolts 51, but smaller in diameter than the root diameter of bolt heads 71. Similarly, as the drive plate 33 and aligning plate 32 continue to be advanced leftwardly, they move longitudinally of and relative to bolts 52 until aligning plate 31 is also engaged and displaced leftwardly, as described above, whereafter the plates move longitudinally relative of bolts 53 and to bolt heads 73 until aligning plate 30 is engaged and advanced to the left. Similarly to the permissive relative motion of bolts 51 through apertures 62, bolts 52 and 53 are permitted to pass slidably through apertures 62 of aligning plates 32 and 31 respectively. The respective bolt heads 72 and 73 of bolts 52 and 53 are permitted to pass through plates 32 and 33 by the provision of enlarged apertures 55 in drive plate 33 and similar apertures (not shown) in aligning plate 32. Thus, bolt heads 71 can engage only drive plate 33, bolt heads 72 can engage only aligning plate 32, and bolt heads 73 can engage only aligning plate 31.

As was noted above, upon completion of the extrusion stroke, appropriately pressurized fluid is admitted to the double acting power cylinders 22 to retract the collapsible feed mechanism from the collapsed position shown in FIG. 3, to the initial position as shown in FIG. 1. Upon the initial rightward movement of the drive plate 33, the aligning plates 30, 31 and 32 remain in the positions shown in FIG. 3; the drive plate moving longitudinally of and relative to the bolts 51, 52 and 53. However, upon the engagement of the drive plate 33 with the heads 71 of the bolts 51, rightward movement is imparted to the aligning plate 32, and the aligning plate is moved rightwardly with the drive plate 33. In a similar manner, the aligning plate 32 and, in turn, aligning plate 31 in cooperation with bolts 53 will pick up aligning plate 30. Thus, the drive plate is retracted by the driving rods 40 and the lost motion linkage between drive plate 33 and aligning plates 31, 32, 33, which linkage is defined by the headed bolts 51, 52 and 53 and the apertures 62, transmits the retractive force successively to said aligning plates.

Retractive movement of the plates will continue until all the aligning plates are returned approximately to the positions shown in FIG. 1, at which time the upwardly biased plungers 82 associated with the cam latch assembly 86 of each aligning plate, will snap into their associated rail notches 84, and the rocker arms 87 will be pivoted clockwise by the bias springs 91 into the locking position shown in FIG. 6. Thus, since the aligning plates are returned to their initial positions substantially simultaneously, they are also latched substantially simultaneously in the positions shown in FIG. 1. Further, it will be noted that the headed bolts also are capable of limiting the rightward movement of the plates should the cam latching assemblies for any reason fail to halt and position the plates.

Thus it can be seen that the present invention provides a collapsible feed mechanism wherein a rod or slender column, in the disclosed apparatus a die ram, can be advanced and retracted under virtually any load condition without bowing the column and with complete control of center line alignment at all times. It will also be appreciated that there is substantially no limit to the length of column to be accommodated since longer columns will require only the addition of more aligning plates and a substitution of longer cage rails.

It will also be recognized by those having skill in this art, that while the collapsible feed mechanism according to the present invention is primarily useful with rods, and in particular slender columns, it is fully appropriate for use in any situation wherein it is desired to advance a rod or rod-like member of any type.

It is to be understood that the above described embodiments are simply illustrative of the principles of the invention. Numerous other modifications may be devised without departing from the scope of the invention.

What is claimed is:

l. Collapsible feed mechanism for advancing under heavy compressive axial loads or selectively retracting along its longitudinal axis a slender column, comprismg:

a drive plate adapted to be secured to said slender column for advancing or selectively retracting said slender column along its longitudinal axis;

a support cage comprised of a plurality of rails azimuthally spaced relative to and extending parallel to the longitudinal axis of said slender column,

said rails slidably engaging said drive plate to support said drive plate to support said drive plate and position said drive plate co-axially of said slender column during the advancement and retraction thereof;

a plurality of aligning plates having apertures adapted to slidably receive said slender column and for providing lateral support to said column upon the advancement thereof;

said rails slidably engaging said aligning plates to support said aligning plates laterally of the longitudinal axis of said slender column and position said aligning plates co-axially of saidslender column during the advancement and retraction thereof;

a plurality of cam latch assemblies, each cam latch assembly individually associated with one aligning plate ,and one of said rails, said cam latch assemblies for latching said aligning plates to said support cage in predetermined positions longitudinally of said slender column, said cam latch assemblies for unlatching said aligning plates in response to the advancement of said drive plate to permit displacement of said aligning plates in the direction of advancement of said drive plate upon the advancement of said slender column, and said cam latch assemblies for relatching said aligning plates to said support cage in said predetermined positions upon the retraction of said slender column; and

lost motion linkage for transmitting retractive forces successively to said aligning plates upon the retraction of said die .plate and said slender column.

2. Apparatus for advancing 'an elongated member under axial compressive load along its longitudinal axis and for simultaneously laterally supporting said elongated member, said apparatus comprising:

a. drivingmeans adapted to be mounted to said elongated member for transmitting force to said elongated member in a direction parallel to the longitudinal axis of said elongated member;

. power means operatively associated with said driv ing means to advance said driving means a predetermined distance parallel to the longitudinal axis of said elongated member thereby to advance said elongated member said predetermined 7 distance; i

c. alignment means having aperture means adapted to guidably receive said elongated member, said alignment means being adapted to laterally support said elongated member;

. support means guiding said driving means along the entire said predetermined distance;

e. said support means guiding said alignment means longitudinally of said elongated member and supporting said alignment means laterally of said elongated member;

f. said alignment means being displaceable in a direction parallel to the longitudinal axis of said elongated member in response to advancement of said driving means through a portion of said predetermined distance;

. latch means operatively interposed between said support means and said alignment means for latching said alignment means to said support means in a predetermined position.

. Apparatus as in claim 2, wherein:

h. said latch means comprises a latch member and a cooperative recess adapted to receive said latch member,

. said latch member is mounted to said alignment means,

j. said recess is provided in said support means.

4. Apparatus as in claim 2, wherein:

h. said driving means is adapted to operatively engage and unlatch said latch means during advancement of said driving means through said predetermined distance.

5. Apparatus as in claim 2, wherein:

h. said alignment means comprises a plurality of alignment plates arranged longitudinally of said elongated member, each alignment plate having a central aperture slidably receiving said elongated member;

i. said latch means comprises a plurality of latches, each of said latches being operatively interposed between said support means and one of said alignment plates for latching its respective alignment plate to said support means in a predetermined position specific to said alignment plate longitudinally of said elongated member.

6. Apparatus as in claim 5, wherein:

j. the plurality of latches is azimuthally spaced relative to the longitudinal axis of said elongated member.

7. Apparatus as in claim 5, wherein:

j. said driving means is adapted to sequentially unlatch said plurality of latches during advancement of said driving means through said predetermined distance.

. Apparatus as in claim 5, wherein:

each latch comprises a latch member and a cooperative recess adapted to receive said latch member,

k. said latch member is mounted to one of said alignment plates,

1. said recess is provided in said support means.

9. Apparatus as in claim 8, wherein:

m. the plurality of latch members and their respective cooperative recesses are azimuthally spaced relative to the longitudinal axis of said elongated member.

10. Apparatus as in claim 2, wherein:

h. said support means comprises a plurality of rail extending parallel to the longitudinal axis of said elongated member for at least said predetermined distance, said rails being azimuthally spaced relative to the longitudinal axis of said elongated member;

. said driving means having a plurality of recesses,

each recess slidably engaging one of said rails;

j. said alignment means having a plurality of recesses,

each recess slidably engaging one of said rails.

11. Apparatus for advancing an elongated member under axial compressive load along its longitudinal axis and for simultaneously laterally supporting said elongated member or selectively for retracting said elongated member, said apparatus comprising:

a. driving means adapted to be mounted to said elongated member for transmitting force to said elongated member in a direction parallel to the longitudinal axis of said elongated member;

b. power means operatively associated with said driving means to advance said driving means a predetermined distance parallel to the longitudinal axis of said elongated member or selectively to retract said driving means thereby to advance said elongated member said predetermined distance or selectively to retract said elongated member;

c. alignment means having aperture means adapted to guidably receive said elongated member, said alignment means being adapted to laterally support said elongated member;

d. support means guiding said driving means along the entire said predetermined distance;

e. said support means guiding said alignment means longitudinally of said elongated member and supporting said alignment means laterally of said elongated member;

f. said alignment means being displaceable in a direction parallel to the longitudinal axis of said elongated member in response to advancement of said driving means through a portion of said predetermined distance;

g. latch means operatively interposed between said support means and said alignment means for latching said alignment means to said support means in a predetermined position.

12. Apparatus as in claim 11, wherein:

h. said latch means comprises a latch member and a cooperative recess adapted to receive said latch member,

. said latch member is mounted to said alignment means,

j. said recess is provided in said support means.

13. Apparatus as in claim 1 1, wherein:

b. said driving means is adapted to operatively engage and unlatch said latch means during advancement of said driving means through said predetermined distance.

14. Apparatus as in claim 11, wherein:

h. said alignment means comprises a plurality of alignment plates arranged longitudinally of said elongated member, each alignment plate having a central aperture slidably receiving said elongated member;

i. said latch means comprises a plurality of latches, each of said latches being operatively interposed between said support means and one of said alignment plates for latching its respective alignment plate to said support means in a predetermined position specific to said alignment plate longitudinally of said elongated member.

15. Apparatus as in claim 14, wherein:

j. the plurality of latches is azimuthally spaced relative to the longitudinal axis of said elongated member.

16. Apparatus as in claim 14, wherein:

j. said driving means is adapted to sequentially unlatch said plurality of latches during advancement of said driving means through said predetermined distance.

17. Apparatus as in claim 14, wherein:

j. each latch comprises a latch member and a cooperative recess adapted to receive said latch member,

k. said latch member is mounted to one of said alignment plates.

1. said recess is provided in said support means.

18. Apparatus as in claim 17, wherein:

m. the plurality of latch members and their respective cooperative recesses are azimuthally spaced relative to the longitudinal axis of said elongated member.

19. Apparatus as in claim 14, further comprising:

j. linkage means operatively interposed between said driving means and said plurality of alignment plates to retract said alignment plates to their respective latched positions upon retraction of said driving means.

20. Apparatus as in claim 19, wherein:

k. said alignment plates are retracted by said linkage means to positions in which all of the latches are simultaneously latched.

21. Apparatus as in claim 14, further comprising:

j. lost motion linkage means operatively interposed between said driving means and said plurality of alignment plates to sequentially retract said alignment plates to their respective latched positions upon retraction of said driving means beyond a predetermined amount.

22. Apparatus as in claim 21, wherein: I

k. said alignment plates are retracted by said lost motion linkage means to positions in which all of the latches are simultaneously latched.

23. Apparatus as in claim 1 1, wherein:

h. said support means comprises a plurality of rails extending parallel to the longitudinal axis of said elongated member for at least said predetermined distance, said rails being azimuthally spaced relative to the longitudinal axis of said elongated member;

i. said driving means having a plurality of recesses,

each recess slidably engagingone of said rails;

j. said alignment means having a plurality of recesses,

each recess slidably engaging one of said rails.

24. Apparatus as in claim 11, further comprising:

h. linkage means operatively interposed between said driving means and said alignment means to retract said alignment means to a position in which said latch means is latched upon retraction of said driving means.

25. Apparatus as in claim 11, further comprising:

h. lost motion linkage means operatively interposed between said driving means and said alignment means to retract said alignment means to a position in which said latch means is latched upon retraction of said driving means beyond a predetermined amount. 

1. Collapsible feed mechanism for advancing under heavy compressive axial loads or selectively retracting along its longitudinal axis a slender column, comprising: a drive plate adapted to be secured to said slender column for advancing or selectively retracting said slender column along its longitudinal axis; a support cage comprised of a plurality of rails azimuthally spaced relative to and extending parallel to the longitudinal axis of said slender column, said rails slidably engaging said drive plate to support said drive plate to support said drive plate and position said drive plate co-axially of said slender column during the advancement and retraction thereof; a plurality of aligning plates having apertures adapted to slidably receive said slender column and for providing lateral support to said column upon the advancement thereof; said rails slidably engaging said aligning plates to support said aligning plates laterally of the longitudinal axis of said slender column and position said aligning plates co-axially of said slender column during the advancement and retraction thereof; a plurality of cam latch assemblies, each cam latch assembly individually associated with one aligning plate and one of said rails, said cam latch assemblies for latching said aligning plates to said support cage in predetermined positions longitudinally of said slender column, said cam latch assemblies for unlatching said aligning plates in response to the advancement of said drive plate to permit displacement of said aligning plates in the direction of advancement of said drive plate upon the advancement of said slender column, and said cam latch assemblies for relatching said aligning plates to said support cage in said predetermined positions upon the retraction of said slender column; and lost motion linkage for transmitting retractive forces successively to said aligning plates upon the retraction of said die plate and said slender column.
 2. Apparatus for advancing an elongated member under axial compressive load along its longitudinal axis and for simultaneously laterally supporting said elongated member, said apparatus comprising: a. driving means adapted to be mounted to said elongated member for transmitting force to said elongated member in a direction parallel to the longitudinal axis of said elongated member; b. power means operatively associated with said driving means to advance said driving means a predetermined distance parallel to the longitudinal axis of said elongated member thereby to advance said elongated member said predetermined distance; c. alignment means having aperture means adapted to guidably receive said elongated member, said alignment means being adapted to laterally support said elongated member; d. support means guiding said driving means along the entire said predetermined distance; e. said support means guiding said alignment means longitudinally of said elongated member and supporting said alignment means laterally of said elongated member; f. said alignment means being displaceable in a direction parallel to the longitudinal axis of said elongated member in response to advancement of said driving means through a portion of said predetermined distance; g. latch means operatively interposed between said support means and said alignment means for latching said alignment means to said support means in a predetermined position.
 3. Apparatus as in claim 2, wherein: h. said latch means comprises a latch member and a cooperative recess adapted to receive said latch member, i. said latch member is mounted to said Alignment means, j. said recess is provided in said support means.
 4. Apparatus as in claim 2, wherein: h. said driving means is adapted to operatively engage and unlatch said latch means during advancement of said driving means through said predetermined distance.
 5. Apparatus as in claim 2, wherein: h. said alignment means comprises a plurality of alignment plates arranged longitudinally of said elongated member, each alignment plate having a central aperture slidably receiving said elongated member; i. said latch means comprises a plurality of latches, each of said latches being operatively interposed between said support means and one of said alignment plates for latching its respective alignment plate to said support means in a predetermined position specific to said alignment plate longitudinally of said elongated member.
 6. Apparatus as in claim 5, wherein: j. the plurality of latches is azimuthally spaced relative to the longitudinal axis of said elongated member.
 7. Apparatus as in claim 5, wherein: j. said driving means is adapted to sequentially unlatch said plurality of latches during advancement of said driving means through said predetermined distance.
 8. Apparatus as in claim 5, wherein: j. each latch comprises a latch member and a cooperative recess adapted to receive said latch member, k. said latch member is mounted to one of said alignment plates, l. said recess is provided in said support means.
 9. Apparatus as in claim 8, wherein: m. the plurality of latch members and their respective cooperative recesses are azimuthally spaced relative to the longitudinal axis of said elongated member.
 10. Apparatus as in claim 2, wherein: h. said support means comprises a plurality of rails extending parallel to the longitudinal axis of said elongated member for at least said predetermined distance, said rails being azimuthally spaced relative to the longitudinal axis of said elongated member; i. said driving means having a plurality of recesses, each recess slidably engaging one of said rails; j. said alignment means having a plurality of recesses, each recess slidably engaging one of said rails.
 11. Apparatus for advancing an elongated member under axial compressive load along its longitudinal axis and for simultaneously laterally supporting said elongated member or selectively for retracting said elongated member, said apparatus comprising: a. driving means adapted to be mounted to said elongated member for transmitting force to said elongated member in a direction parallel to the longitudinal axis of said elongated member; b. power means operatively associated with said driving means to advance said driving means a predetermined distance parallel to the longitudinal axis of said elongated member or selectively to retract said driving means thereby to advance said elongated member said predetermined distance or selectively to retract said elongated member; c. alignment means having aperture means adapted to guidably receive said elongated member, said alignment means being adapted to laterally support said elongated member; d. support means guiding said driving means along the entire said predetermined distance; e. said support means guiding said alignment means longitudinally of said elongated member and supporting said alignment means laterally of said elongated member; f. said alignment means being displaceable in a direction parallel to the longitudinal axis of said elongated member in response to advancement of said driving means through a portion of said predetermined distance; g. latch means operatively interposed between said support means and said alignment means for latching said alignment means to said support means in a predetermined position.
 12. Apparatus as in claim 11, wherein: h. said latch means comprises a latch member and a cooperative recess adapted to receive said latch member, i. said latch member is mounted To said alignment means, j. said recess is provided in said support means.
 13. Apparatus as in claim 11, wherein: h. said driving means is adapted to operatively engage and unlatch said latch means during advancement of said driving means through said predetermined distance.
 14. Apparatus as in claim 11, wherein: h. said alignment means comprises a plurality of alignment plates arranged longitudinally of said elongated member, each alignment plate having a central aperture slidably receiving said elongated member; i. said latch means comprises a plurality of latches, each of said latches being operatively interposed between said support means and one of said alignment plates for latching its respective alignment plate to said support means in a predetermined position specific to said alignment plate longitudinally of said elongated member.
 15. Apparatus as in claim 14, wherein: j. the plurality of latches is azimuthally spaced relative to the longitudinal axis of said elongated member.
 16. Apparatus as in claim 14, wherein: j. said driving means is adapted to sequentially unlatch said plurality of latches during advancement of said driving means through said predetermined distance.
 17. Apparatus as in claim 14, wherein: j. each latch comprises a latch member and a cooperative recess adapted to receive said latch member, k. said latch member is mounted to one of said alignment plates. l. said recess is provided in said support means.
 18. Apparatus as in claim 17, wherein: m. the plurality of latch members and their respective cooperative recesses are azimuthally spaced relative to the longitudinal axis of said elongated member.
 19. Apparatus as in claim 14, further comprising: j. linkage means operatively interposed between said driving means and said plurality of alignment plates to retract said alignment plates to their respective latched positions upon retraction of said driving means.
 20. Apparatus as in claim 19, wherein: k. said alignment plates are retracted by said linkage means to positions in which all of the latches are simultaneously latched.
 21. Apparatus as in claim 14, further comprising: j. lost motion linkage means operatively interposed between said driving means and said plurality of alignment plates to sequentially retract said alignment plates to their respective latched positions upon retraction of said driving means beyond a predetermined amount.
 22. Apparatus as in claim 21, wherein: k. said alignment plates are retracted by said lost motion linkage means to positions in which all of the latches are simultaneously latched.
 23. Apparatus as in claim 11, wherein: h. said support means comprises a plurality of rails extending parallel to the longitudinal axis of said elongated member for at least said predetermined distance, said rails being azimuthally spaced relative to the longitudinal axis of said elongated member; i. said driving means having a plurality of recesses, each recess slidably engaging one of said rails; j. said alignment means having a plurality of recesses, each recess slidably engaging one of said rails.
 24. Apparatus as in claim 11, further comprising: h. linkage means operatively interposed between said driving means and said alignment means to retract said alignment means to a position in which said latch means is latched upon retraction of said driving means.
 25. Apparatus as in claim 11, further comprising: h. lost motion linkage means operatively interposed between said driving means and said alignment means to retract said alignment means to a position in which said latch means is latched upon retraction of said driving means beyond a predetermined amount. 